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a0375156ca
We don't need to set s_dirt in most of the ext4 code when journaling is enabled. In ext3/4 some of the summary statistics for # of free inodes, blocks, and directories are calculated from the per-block group statistics when the file system is mounted or unmounted. As a result the superblock doesn't have to be updated, either via the journal or by setting s_dirt. There are a few exceptions, most notably when resizing the file system, where the superblock needs to be modified --- and in that case it should be done as a journalled operation if possible, and s_dirt set only in no-journal mode. This patch will optimize out some unneeded disk writes when using ext4 with a journal. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
742 lines
21 KiB
C
742 lines
21 KiB
C
/*
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* linux/fs/ext4/balloc.c
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*
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* Enhanced block allocation by Stephen Tweedie (sct@redhat.com), 1993
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* Big-endian to little-endian byte-swapping/bitmaps by
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* David S. Miller (davem@caip.rutgers.edu), 1995
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*/
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#include <linux/time.h>
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#include <linux/capability.h>
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#include <linux/fs.h>
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#include <linux/jbd2.h>
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#include <linux/quotaops.h>
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#include <linux/buffer_head.h>
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#include "ext4.h"
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#include "ext4_jbd2.h"
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#include "mballoc.h"
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/*
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* balloc.c contains the blocks allocation and deallocation routines
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*/
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/*
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* Calculate the block group number and offset, given a block number
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*/
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void ext4_get_group_no_and_offset(struct super_block *sb, ext4_fsblk_t blocknr,
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ext4_group_t *blockgrpp, ext4_grpblk_t *offsetp)
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{
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struct ext4_super_block *es = EXT4_SB(sb)->s_es;
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ext4_grpblk_t offset;
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blocknr = blocknr - le32_to_cpu(es->s_first_data_block);
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offset = do_div(blocknr, EXT4_BLOCKS_PER_GROUP(sb));
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if (offsetp)
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*offsetp = offset;
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if (blockgrpp)
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*blockgrpp = blocknr;
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}
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static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block,
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ext4_group_t block_group)
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{
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ext4_group_t actual_group;
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ext4_get_group_no_and_offset(sb, block, &actual_group, NULL);
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if (actual_group == block_group)
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return 1;
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return 0;
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}
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static int ext4_group_used_meta_blocks(struct super_block *sb,
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ext4_group_t block_group,
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struct ext4_group_desc *gdp)
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{
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ext4_fsblk_t tmp;
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struct ext4_sb_info *sbi = EXT4_SB(sb);
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/* block bitmap, inode bitmap, and inode table blocks */
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int used_blocks = sbi->s_itb_per_group + 2;
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if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
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if (!ext4_block_in_group(sb, ext4_block_bitmap(sb, gdp),
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block_group))
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used_blocks--;
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if (!ext4_block_in_group(sb, ext4_inode_bitmap(sb, gdp),
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block_group))
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used_blocks--;
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tmp = ext4_inode_table(sb, gdp);
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for (; tmp < ext4_inode_table(sb, gdp) +
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sbi->s_itb_per_group; tmp++) {
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if (!ext4_block_in_group(sb, tmp, block_group))
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used_blocks -= 1;
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}
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}
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return used_blocks;
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}
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/* Initializes an uninitialized block bitmap if given, and returns the
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* number of blocks free in the group. */
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unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
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ext4_group_t block_group, struct ext4_group_desc *gdp)
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{
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int bit, bit_max;
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ext4_group_t ngroups = ext4_get_groups_count(sb);
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unsigned free_blocks, group_blocks;
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struct ext4_sb_info *sbi = EXT4_SB(sb);
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if (bh) {
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J_ASSERT_BH(bh, buffer_locked(bh));
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/* If checksum is bad mark all blocks used to prevent allocation
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* essentially implementing a per-group read-only flag. */
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if (!ext4_group_desc_csum_verify(sbi, block_group, gdp)) {
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ext4_error(sb, "Checksum bad for group %u",
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block_group);
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ext4_free_blks_set(sb, gdp, 0);
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ext4_free_inodes_set(sb, gdp, 0);
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ext4_itable_unused_set(sb, gdp, 0);
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memset(bh->b_data, 0xff, sb->s_blocksize);
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return 0;
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}
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memset(bh->b_data, 0, sb->s_blocksize);
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}
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/* Check for superblock and gdt backups in this group */
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bit_max = ext4_bg_has_super(sb, block_group);
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if (!EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_META_BG) ||
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block_group < le32_to_cpu(sbi->s_es->s_first_meta_bg) *
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sbi->s_desc_per_block) {
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if (bit_max) {
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bit_max += ext4_bg_num_gdb(sb, block_group);
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bit_max +=
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le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
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}
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} else { /* For META_BG_BLOCK_GROUPS */
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bit_max += ext4_bg_num_gdb(sb, block_group);
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}
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if (block_group == ngroups - 1) {
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/*
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* Even though mke2fs always initialize first and last group
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* if some other tool enabled the EXT4_BG_BLOCK_UNINIT we need
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* to make sure we calculate the right free blocks
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*/
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group_blocks = ext4_blocks_count(sbi->s_es) -
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ext4_group_first_block_no(sb, ngroups - 1);
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} else {
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group_blocks = EXT4_BLOCKS_PER_GROUP(sb);
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}
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free_blocks = group_blocks - bit_max;
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if (bh) {
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ext4_fsblk_t start, tmp;
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int flex_bg = 0;
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for (bit = 0; bit < bit_max; bit++)
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ext4_set_bit(bit, bh->b_data);
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start = ext4_group_first_block_no(sb, block_group);
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if (EXT4_HAS_INCOMPAT_FEATURE(sb,
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EXT4_FEATURE_INCOMPAT_FLEX_BG))
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flex_bg = 1;
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/* Set bits for block and inode bitmaps, and inode table */
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tmp = ext4_block_bitmap(sb, gdp);
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if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
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ext4_set_bit(tmp - start, bh->b_data);
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tmp = ext4_inode_bitmap(sb, gdp);
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if (!flex_bg || ext4_block_in_group(sb, tmp, block_group))
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ext4_set_bit(tmp - start, bh->b_data);
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tmp = ext4_inode_table(sb, gdp);
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for (; tmp < ext4_inode_table(sb, gdp) +
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sbi->s_itb_per_group; tmp++) {
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if (!flex_bg ||
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ext4_block_in_group(sb, tmp, block_group))
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ext4_set_bit(tmp - start, bh->b_data);
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}
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/*
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* Also if the number of blocks within the group is
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* less than the blocksize * 8 ( which is the size
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* of bitmap ), set rest of the block bitmap to 1
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*/
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mark_bitmap_end(group_blocks, sb->s_blocksize * 8, bh->b_data);
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}
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return free_blocks - ext4_group_used_meta_blocks(sb, block_group, gdp);
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}
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/*
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* The free blocks are managed by bitmaps. A file system contains several
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* blocks groups. Each group contains 1 bitmap block for blocks, 1 bitmap
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* block for inodes, N blocks for the inode table and data blocks.
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*
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* The file system contains group descriptors which are located after the
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* super block. Each descriptor contains the number of the bitmap block and
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* the free blocks count in the block. The descriptors are loaded in memory
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* when a file system is mounted (see ext4_fill_super).
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*/
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/**
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* ext4_get_group_desc() -- load group descriptor from disk
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* @sb: super block
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* @block_group: given block group
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* @bh: pointer to the buffer head to store the block
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* group descriptor
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*/
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struct ext4_group_desc * ext4_get_group_desc(struct super_block *sb,
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ext4_group_t block_group,
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struct buffer_head **bh)
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{
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unsigned int group_desc;
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unsigned int offset;
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ext4_group_t ngroups = ext4_get_groups_count(sb);
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struct ext4_group_desc *desc;
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struct ext4_sb_info *sbi = EXT4_SB(sb);
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if (block_group >= ngroups) {
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ext4_error(sb, "block_group >= groups_count - block_group = %u,"
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" groups_count = %u", block_group, ngroups);
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return NULL;
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}
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group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
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offset = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
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if (!sbi->s_group_desc[group_desc]) {
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ext4_error(sb, "Group descriptor not loaded - "
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"block_group = %u, group_desc = %u, desc = %u",
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block_group, group_desc, offset);
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return NULL;
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}
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desc = (struct ext4_group_desc *)(
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(__u8 *)sbi->s_group_desc[group_desc]->b_data +
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offset * EXT4_DESC_SIZE(sb));
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if (bh)
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*bh = sbi->s_group_desc[group_desc];
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return desc;
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}
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static int ext4_valid_block_bitmap(struct super_block *sb,
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struct ext4_group_desc *desc,
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unsigned int block_group,
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struct buffer_head *bh)
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{
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ext4_grpblk_t offset;
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ext4_grpblk_t next_zero_bit;
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ext4_fsblk_t bitmap_blk;
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ext4_fsblk_t group_first_block;
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if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) {
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/* with FLEX_BG, the inode/block bitmaps and itable
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* blocks may not be in the group at all
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* so the bitmap validation will be skipped for those groups
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* or it has to also read the block group where the bitmaps
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* are located to verify they are set.
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*/
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return 1;
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}
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group_first_block = ext4_group_first_block_no(sb, block_group);
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/* check whether block bitmap block number is set */
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bitmap_blk = ext4_block_bitmap(sb, desc);
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offset = bitmap_blk - group_first_block;
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if (!ext4_test_bit(offset, bh->b_data))
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/* bad block bitmap */
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goto err_out;
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/* check whether the inode bitmap block number is set */
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bitmap_blk = ext4_inode_bitmap(sb, desc);
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offset = bitmap_blk - group_first_block;
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if (!ext4_test_bit(offset, bh->b_data))
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/* bad block bitmap */
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goto err_out;
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/* check whether the inode table block number is set */
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bitmap_blk = ext4_inode_table(sb, desc);
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offset = bitmap_blk - group_first_block;
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next_zero_bit = ext4_find_next_zero_bit(bh->b_data,
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offset + EXT4_SB(sb)->s_itb_per_group,
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offset);
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if (next_zero_bit >= offset + EXT4_SB(sb)->s_itb_per_group)
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/* good bitmap for inode tables */
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return 1;
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err_out:
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ext4_error(sb, "Invalid block bitmap - block_group = %d, block = %llu",
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block_group, bitmap_blk);
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return 0;
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}
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/**
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* ext4_read_block_bitmap()
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* @sb: super block
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* @block_group: given block group
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*
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* Read the bitmap for a given block_group,and validate the
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* bits for block/inode/inode tables are set in the bitmaps
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*
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* Return buffer_head on success or NULL in case of failure.
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*/
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struct buffer_head *
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ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
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{
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struct ext4_group_desc *desc;
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struct buffer_head *bh = NULL;
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ext4_fsblk_t bitmap_blk;
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desc = ext4_get_group_desc(sb, block_group, NULL);
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if (!desc)
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return NULL;
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bitmap_blk = ext4_block_bitmap(sb, desc);
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bh = sb_getblk(sb, bitmap_blk);
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if (unlikely(!bh)) {
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ext4_error(sb, "Cannot read block bitmap - "
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"block_group = %u, block_bitmap = %llu",
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block_group, bitmap_blk);
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return NULL;
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}
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if (bitmap_uptodate(bh))
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return bh;
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lock_buffer(bh);
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if (bitmap_uptodate(bh)) {
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unlock_buffer(bh);
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return bh;
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}
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ext4_lock_group(sb, block_group);
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if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
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ext4_init_block_bitmap(sb, bh, block_group, desc);
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set_bitmap_uptodate(bh);
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set_buffer_uptodate(bh);
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ext4_unlock_group(sb, block_group);
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unlock_buffer(bh);
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return bh;
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}
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ext4_unlock_group(sb, block_group);
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if (buffer_uptodate(bh)) {
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/*
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* if not uninit if bh is uptodate,
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* bitmap is also uptodate
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*/
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set_bitmap_uptodate(bh);
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unlock_buffer(bh);
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return bh;
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}
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/*
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* submit the buffer_head for read. We can
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* safely mark the bitmap as uptodate now.
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* We do it here so the bitmap uptodate bit
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* get set with buffer lock held.
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*/
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set_bitmap_uptodate(bh);
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if (bh_submit_read(bh) < 0) {
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put_bh(bh);
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ext4_error(sb, "Cannot read block bitmap - "
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"block_group = %u, block_bitmap = %llu",
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block_group, bitmap_blk);
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return NULL;
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}
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ext4_valid_block_bitmap(sb, desc, block_group, bh);
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/*
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* file system mounted not to panic on error,
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* continue with corrupt bitmap
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*/
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return bh;
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}
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/**
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* ext4_add_groupblocks() -- Add given blocks to an existing group
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* @handle: handle to this transaction
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* @sb: super block
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* @block: start physcial block to add to the block group
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* @count: number of blocks to free
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*
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* This marks the blocks as free in the bitmap. We ask the
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* mballoc to reload the buddy after this by setting group
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* EXT4_GROUP_INFO_NEED_INIT_BIT flag
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*/
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void ext4_add_groupblocks(handle_t *handle, struct super_block *sb,
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ext4_fsblk_t block, unsigned long count)
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{
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struct buffer_head *bitmap_bh = NULL;
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struct buffer_head *gd_bh;
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ext4_group_t block_group;
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ext4_grpblk_t bit;
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unsigned int i;
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struct ext4_group_desc *desc;
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struct ext4_sb_info *sbi = EXT4_SB(sb);
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int err = 0, ret, blk_free_count;
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ext4_grpblk_t blocks_freed;
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struct ext4_group_info *grp;
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ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
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ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
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grp = ext4_get_group_info(sb, block_group);
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/*
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* Check to see if we are freeing blocks across a group
|
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* boundary.
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*/
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if (bit + count > EXT4_BLOCKS_PER_GROUP(sb)) {
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goto error_return;
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}
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bitmap_bh = ext4_read_block_bitmap(sb, block_group);
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if (!bitmap_bh)
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goto error_return;
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desc = ext4_get_group_desc(sb, block_group, &gd_bh);
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if (!desc)
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goto error_return;
|
|
|
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if (in_range(ext4_block_bitmap(sb, desc), block, count) ||
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in_range(ext4_inode_bitmap(sb, desc), block, count) ||
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in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
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in_range(block + count - 1, ext4_inode_table(sb, desc),
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sbi->s_itb_per_group)) {
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ext4_error(sb, "Adding blocks in system zones - "
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"Block = %llu, count = %lu",
|
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block, count);
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goto error_return;
|
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}
|
|
|
|
/*
|
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* We are about to add blocks to the bitmap,
|
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* so we need undo access.
|
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*/
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BUFFER_TRACE(bitmap_bh, "getting undo access");
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err = ext4_journal_get_undo_access(handle, bitmap_bh);
|
|
if (err)
|
|
goto error_return;
|
|
|
|
/*
|
|
* We are about to modify some metadata. Call the journal APIs
|
|
* to unshare ->b_data if a currently-committing transaction is
|
|
* using it
|
|
*/
|
|
BUFFER_TRACE(gd_bh, "get_write_access");
|
|
err = ext4_journal_get_write_access(handle, gd_bh);
|
|
if (err)
|
|
goto error_return;
|
|
/*
|
|
* make sure we don't allow a parallel init on other groups in the
|
|
* same buddy cache
|
|
*/
|
|
down_write(&grp->alloc_sem);
|
|
for (i = 0, blocks_freed = 0; i < count; i++) {
|
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BUFFER_TRACE(bitmap_bh, "clear bit");
|
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if (!ext4_clear_bit_atomic(ext4_group_lock_ptr(sb, block_group),
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bit + i, bitmap_bh->b_data)) {
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ext4_error(sb, "bit already cleared for block %llu",
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(ext4_fsblk_t)(block + i));
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BUFFER_TRACE(bitmap_bh, "bit already cleared");
|
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} else {
|
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blocks_freed++;
|
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}
|
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}
|
|
ext4_lock_group(sb, block_group);
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|
blk_free_count = blocks_freed + ext4_free_blks_count(sb, desc);
|
|
ext4_free_blks_set(sb, desc, blk_free_count);
|
|
desc->bg_checksum = ext4_group_desc_csum(sbi, block_group, desc);
|
|
ext4_unlock_group(sb, block_group);
|
|
percpu_counter_add(&sbi->s_freeblocks_counter, blocks_freed);
|
|
|
|
if (sbi->s_log_groups_per_flex) {
|
|
ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
|
|
atomic_add(blocks_freed,
|
|
&sbi->s_flex_groups[flex_group].free_blocks);
|
|
}
|
|
/*
|
|
* request to reload the buddy with the
|
|
* new bitmap information
|
|
*/
|
|
set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
|
|
grp->bb_free += blocks_freed;
|
|
up_write(&grp->alloc_sem);
|
|
|
|
/* We dirtied the bitmap block */
|
|
BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
|
|
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
|
|
|
|
/* And the group descriptor block */
|
|
BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
|
|
ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
|
|
if (!err)
|
|
err = ret;
|
|
|
|
error_return:
|
|
brelse(bitmap_bh);
|
|
ext4_std_error(sb, err);
|
|
return;
|
|
}
|
|
|
|
/**
|
|
* ext4_has_free_blocks()
|
|
* @sbi: in-core super block structure.
|
|
* @nblocks: number of needed blocks
|
|
*
|
|
* Check if filesystem has nblocks free & available for allocation.
|
|
* On success return 1, return 0 on failure.
|
|
*/
|
|
int ext4_has_free_blocks(struct ext4_sb_info *sbi, s64 nblocks)
|
|
{
|
|
s64 free_blocks, dirty_blocks, root_blocks;
|
|
struct percpu_counter *fbc = &sbi->s_freeblocks_counter;
|
|
struct percpu_counter *dbc = &sbi->s_dirtyblocks_counter;
|
|
|
|
free_blocks = percpu_counter_read_positive(fbc);
|
|
dirty_blocks = percpu_counter_read_positive(dbc);
|
|
root_blocks = ext4_r_blocks_count(sbi->s_es);
|
|
|
|
if (free_blocks - (nblocks + root_blocks + dirty_blocks) <
|
|
EXT4_FREEBLOCKS_WATERMARK) {
|
|
free_blocks = percpu_counter_sum_positive(fbc);
|
|
dirty_blocks = percpu_counter_sum_positive(dbc);
|
|
if (dirty_blocks < 0) {
|
|
printk(KERN_CRIT "Dirty block accounting "
|
|
"went wrong %lld\n",
|
|
(long long)dirty_blocks);
|
|
}
|
|
}
|
|
/* Check whether we have space after
|
|
* accounting for current dirty blocks & root reserved blocks.
|
|
*/
|
|
if (free_blocks >= ((root_blocks + nblocks) + dirty_blocks))
|
|
return 1;
|
|
|
|
/* Hm, nope. Are (enough) root reserved blocks available? */
|
|
if (sbi->s_resuid == current_fsuid() ||
|
|
((sbi->s_resgid != 0) && in_group_p(sbi->s_resgid)) ||
|
|
capable(CAP_SYS_RESOURCE)) {
|
|
if (free_blocks >= (nblocks + dirty_blocks))
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
int ext4_claim_free_blocks(struct ext4_sb_info *sbi,
|
|
s64 nblocks)
|
|
{
|
|
if (ext4_has_free_blocks(sbi, nblocks)) {
|
|
percpu_counter_add(&sbi->s_dirtyblocks_counter, nblocks);
|
|
return 0;
|
|
} else
|
|
return -ENOSPC;
|
|
}
|
|
|
|
/**
|
|
* ext4_should_retry_alloc()
|
|
* @sb: super block
|
|
* @retries number of attemps has been made
|
|
*
|
|
* ext4_should_retry_alloc() is called when ENOSPC is returned, and if
|
|
* it is profitable to retry the operation, this function will wait
|
|
* for the current or commiting transaction to complete, and then
|
|
* return TRUE.
|
|
*
|
|
* if the total number of retries exceed three times, return FALSE.
|
|
*/
|
|
int ext4_should_retry_alloc(struct super_block *sb, int *retries)
|
|
{
|
|
if (!ext4_has_free_blocks(EXT4_SB(sb), 1) ||
|
|
(*retries)++ > 3 ||
|
|
!EXT4_SB(sb)->s_journal)
|
|
return 0;
|
|
|
|
jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
|
|
|
|
return jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
|
|
}
|
|
|
|
/*
|
|
* ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
|
|
*
|
|
* @handle: handle to this transaction
|
|
* @inode: file inode
|
|
* @goal: given target block(filesystem wide)
|
|
* @count: pointer to total number of blocks needed
|
|
* @errp: error code
|
|
*
|
|
* Return 1st allocated block number on success, *count stores total account
|
|
* error stores in errp pointer
|
|
*/
|
|
ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
|
|
ext4_fsblk_t goal, unsigned long *count, int *errp)
|
|
{
|
|
struct ext4_allocation_request ar;
|
|
ext4_fsblk_t ret;
|
|
|
|
memset(&ar, 0, sizeof(ar));
|
|
/* Fill with neighbour allocated blocks */
|
|
ar.inode = inode;
|
|
ar.goal = goal;
|
|
ar.len = count ? *count : 1;
|
|
|
|
ret = ext4_mb_new_blocks(handle, &ar, errp);
|
|
if (count)
|
|
*count = ar.len;
|
|
/*
|
|
* Account for the allocated meta blocks. We will never
|
|
* fail EDQUOT for metdata, but we do account for it.
|
|
*/
|
|
if (!(*errp) && EXT4_I(inode)->i_delalloc_reserved_flag) {
|
|
spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
EXT4_I(inode)->i_allocated_meta_blocks += ar.len;
|
|
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
|
|
dquot_alloc_block_nofail(inode, ar.len);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* ext4_count_free_blocks() -- count filesystem free blocks
|
|
* @sb: superblock
|
|
*
|
|
* Adds up the number of free blocks from each block group.
|
|
*/
|
|
ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb)
|
|
{
|
|
ext4_fsblk_t desc_count;
|
|
struct ext4_group_desc *gdp;
|
|
ext4_group_t i;
|
|
ext4_group_t ngroups = ext4_get_groups_count(sb);
|
|
#ifdef EXT4FS_DEBUG
|
|
struct ext4_super_block *es;
|
|
ext4_fsblk_t bitmap_count;
|
|
unsigned int x;
|
|
struct buffer_head *bitmap_bh = NULL;
|
|
|
|
es = EXT4_SB(sb)->s_es;
|
|
desc_count = 0;
|
|
bitmap_count = 0;
|
|
gdp = NULL;
|
|
|
|
for (i = 0; i < ngroups; i++) {
|
|
gdp = ext4_get_group_desc(sb, i, NULL);
|
|
if (!gdp)
|
|
continue;
|
|
desc_count += ext4_free_blks_count(sb, gdp);
|
|
brelse(bitmap_bh);
|
|
bitmap_bh = ext4_read_block_bitmap(sb, i);
|
|
if (bitmap_bh == NULL)
|
|
continue;
|
|
|
|
x = ext4_count_free(bitmap_bh, sb->s_blocksize);
|
|
printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n",
|
|
i, ext4_free_blks_count(sb, gdp), x);
|
|
bitmap_count += x;
|
|
}
|
|
brelse(bitmap_bh);
|
|
printk(KERN_DEBUG "ext4_count_free_blocks: stored = %llu"
|
|
", computed = %llu, %llu\n", ext4_free_blocks_count(es),
|
|
desc_count, bitmap_count);
|
|
return bitmap_count;
|
|
#else
|
|
desc_count = 0;
|
|
for (i = 0; i < ngroups; i++) {
|
|
gdp = ext4_get_group_desc(sb, i, NULL);
|
|
if (!gdp)
|
|
continue;
|
|
desc_count += ext4_free_blks_count(sb, gdp);
|
|
}
|
|
|
|
return desc_count;
|
|
#endif
|
|
}
|
|
|
|
static inline int test_root(ext4_group_t a, int b)
|
|
{
|
|
int num = b;
|
|
|
|
while (a > num)
|
|
num *= b;
|
|
return num == a;
|
|
}
|
|
|
|
static int ext4_group_sparse(ext4_group_t group)
|
|
{
|
|
if (group <= 1)
|
|
return 1;
|
|
if (!(group & 1))
|
|
return 0;
|
|
return (test_root(group, 7) || test_root(group, 5) ||
|
|
test_root(group, 3));
|
|
}
|
|
|
|
/**
|
|
* ext4_bg_has_super - number of blocks used by the superblock in group
|
|
* @sb: superblock for filesystem
|
|
* @group: group number to check
|
|
*
|
|
* Return the number of blocks used by the superblock (primary or backup)
|
|
* in this group. Currently this will be only 0 or 1.
|
|
*/
|
|
int ext4_bg_has_super(struct super_block *sb, ext4_group_t group)
|
|
{
|
|
if (EXT4_HAS_RO_COMPAT_FEATURE(sb,
|
|
EXT4_FEATURE_RO_COMPAT_SPARSE_SUPER) &&
|
|
!ext4_group_sparse(group))
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
static unsigned long ext4_bg_num_gdb_meta(struct super_block *sb,
|
|
ext4_group_t group)
|
|
{
|
|
unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
|
|
ext4_group_t first = metagroup * EXT4_DESC_PER_BLOCK(sb);
|
|
ext4_group_t last = first + EXT4_DESC_PER_BLOCK(sb) - 1;
|
|
|
|
if (group == first || group == first + 1 || group == last)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
static unsigned long ext4_bg_num_gdb_nometa(struct super_block *sb,
|
|
ext4_group_t group)
|
|
{
|
|
if (!ext4_bg_has_super(sb, group))
|
|
return 0;
|
|
|
|
if (EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG))
|
|
return le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
|
|
else
|
|
return EXT4_SB(sb)->s_gdb_count;
|
|
}
|
|
|
|
/**
|
|
* ext4_bg_num_gdb - number of blocks used by the group table in group
|
|
* @sb: superblock for filesystem
|
|
* @group: group number to check
|
|
*
|
|
* Return the number of blocks used by the group descriptor table
|
|
* (primary or backup) in this group. In the future there may be a
|
|
* different number of descriptor blocks in each group.
|
|
*/
|
|
unsigned long ext4_bg_num_gdb(struct super_block *sb, ext4_group_t group)
|
|
{
|
|
unsigned long first_meta_bg =
|
|
le32_to_cpu(EXT4_SB(sb)->s_es->s_first_meta_bg);
|
|
unsigned long metagroup = group / EXT4_DESC_PER_BLOCK(sb);
|
|
|
|
if (!EXT4_HAS_INCOMPAT_FEATURE(sb,EXT4_FEATURE_INCOMPAT_META_BG) ||
|
|
metagroup < first_meta_bg)
|
|
return ext4_bg_num_gdb_nometa(sb, group);
|
|
|
|
return ext4_bg_num_gdb_meta(sb,group);
|
|
|
|
}
|
|
|